The present invention relates generally to hand-held electronic apparatus, such as radio display pagers, which comprise an inductive element that produces a transient surge current, and more specifically to a power supply circuit for such apparatus.
Conventional radio display pagers include a vibrator for alerting users on receiving a message. The use of vibrator is particularly useful when a pager is used in a noisy environment or in an environment in which silence is observed. Such vibrators comprise an inductive element that drains a large transient current from the battery and a substantial voltage drop results if the internal resistance of the battery is high. If the pager includes a memory, stored data would be lost by the voltage drop. Since the internal resistance of a battery increases as its size decreases, the use of small batteries to meet compact design requirement would produce instances in which loss of stored data is likely to occur. Although the use of a high capacity battery would solve the problem, battery sizes are standardized, and hence an increase in battery size requires a prohibitively large space in the hand-held apparatus.